GlaxoSmithKline Plc cut the prices on its range of HIV drugs offered to developing countries, marking the fifth such discount since 1997. The most significant reduction is an almost 40 percent cut on Ziagen, a pill the World Health Organisation recommends as a first- and second-line treatment particularly for children. The average discount across its 14 not-for-profit HIV medicines was 21 percent, the company said on Tuesday.